Pancreatic ductal adenocarcinoma (PDAC) is highly lethal and resistant to conventional therapies, including chemo‐, radio‐, and immunotherapy. In this study, it is first determined that a combination of dihydroartemisinin (DHA) and RSL‐3 (a glutathione peroxidase 4 (GPX4) inhibitor) markedly induced ferroptosis of PDAC tumor cells. A mechanistic study revealed that DHA can react with iron ions to generate carbon radicals and deplete intracellular glutathione, thereby cumulatively triggering the lipid peroxidation of tumor cells with RSL‐3‐mediated GPX4 inhibition. A DHA‐conjugated amphiphilic copolymer is subsequently synthesized, and intracellular acidity and oxidation dual‐responsive DHA nanoparticles are further engineered for the tumor‐specific co‐delivery of DHA and RSL‐3. The resultant nanoparticles (PDBA@RSL‐3) efficiently induce ferroptosis of tumor cells in the Panc02 tumor‐bearing immune‐deficient mouse model, and elicit T‐cell‐based antitumor immunity in the immune‐competent mouse model. The combination of PDBA@RSL‐3 nanoparticles and programmed death ligand 1 blockade therapy efficiently inhibits PDAC tumor growth in the immune‐competent mouse models. This study may provide novel insights for treatment of PDAC with ferroptosis‐based immunotherapy.

Anaplastic thyroid carcinoma (ATC) is aggressive and lethal with extrathyroidal invasion, distant metastasis, and resistance to conventional therapies. Cancer stem cells (CSCs) are proposed to be responsible for high recurrence rate in ATC. MicroRNAs (miRNAs) have recently been found as an important class of cellular regulators of ATC carcinogenesis. Identification of CSC-related miRNAs and targets is therefore a priority for the development of new therapeutic paradigms. Patient-derived ATC cells were cultured in conditional media on poly-hema-treated dish. ATC CSCs were isolated and enriched through as a series of steps including initial isolation of sphere-forming CSC population, subsequent amplification of this CSC population in a xenograft model treated with cisplatin, and purification of CSCs from xenograft tumors followed by final enrichment using sphere-forming assays. Expression of CSC markers was measured by flow cytometry, immunofluorescence staining, qPCR and western blot analyses. Expression of miRNAs in ATC-CSCs was profiled by microarray analysis. Proliferation and differentiation rates were determined based on the size of spheres formed in vitro and tumors formed in vivo. We successfully isolated and enriched an ATC-CSC population. We identified 17 miRNAs differentially expressed in primary ATC cells vs. ATC-CSCs, among which miRNA-148a was significantly downregulated in ATC-CSCs. Overexpression of miRNA148a in ATC-CSCs induced cell cycle arrest and loss of stem cell characteristics. In addition, we identified INO80 as a target gene of miR-148a. The expression of INO80 was upregulated in ATC-CSCs and downregulated upon miRNA-148 overexpression. Overexpression of miRNA-148a and knockdown of INO80 acted synergistically to decrease the expression of stem cell marker genes as well as to attenuate stem cell-specific properties including the ability to form tumors. This study identified novel contrasting roles for miR-148a and INO80 in the regulation of the stemness of ATC-CSCs and their capacity to initiate tumor formation. Our findings may open a new avenue for therapeutic development against ATC that targets INO80 in the CSCs through enhancing miRNA-148a levels.

PTEN is one of the direct target genes of miR-21. Thus, phosphatase gene and its downstream AKT and PI3K expression levels can be regulated by regulating the expression levels of miR-21, which in turn regulates the development of CRC.

Herein, folic acid (FA) conjugated Poly(d,l-lactide-co-glycolide) (PLGA)-lipid composites (FA-PL) were developed as nanocarriers for the targeted delivery of insoluble anti-cancer drug paclitaxel (PTX), resulting FA-PLP nanoparticles. Furthermore, 131I, as a radioactive tracer, was used to label FA-PLP nanoparticles (FA-PLP-131I) to evaluate their cell uptake activity, in vivo blood circulation, and biodistribution. The FA-PLP-131I nanoparticles had a spherical morphology with great stability, a narrow size distribution (165.6 and 181.2 nm), and −22.1 mV in average zeta potential. Confocal laser scanning microscopy indicated that the targeting molecule FA promotes PLP-131I uptake by melanoma B16F10 cells, which was further confirmed by the cell incorporation rate via 131I activity detection as measured by a gamma counter. FA-PLP-131I without PTX (FA-PL-131I) shows minor cytotoxicity, good biocompatibility, while FA-PLP-131I was demonstrated to have efficient cell viability suppression compared to free PTX and PLP-131I. Following intravenous injection, the blood circulation half-life of free PTX (t 1/2 = 5.4 ± 0.23 h) was prolonged to 18.5 ± 0.5 h by FA-PLP-131I. Through FA targeting, the tumor uptake of FA-PLP-131I was approximately 4.41- and 12.8-fold higher compared to that of PLP-131I and free PTX-131I, respectively. Moreover, following 40 days of treatment, FA-PLP-131I showed an improved tumor inhibition effect compared to free PTX and PLP-131I, with no relapse and no remarkable systemic in vivo toxicity. The results demonstrate that the 131I-labeled PLGA-lipid nanoparticle can be simultaneously applied for targeted drug delivery and reliable tracking of drugs in vivo.Electronic supplementary materialThe online version of this article (doi:10.1186/s11671-017-2140-7) contains supplementary material, which is available to authorized users.

AIMTo explore expression of angiopoietin-like protein 2 (ANGPTL2) and its effect on biological behavior such as proliferation and invasiveness in gastric cancer.METHODSWestern blotting was used to detect expression of ANGPTL2 in 60 human normal gastric tissues, 60 human gastric cancer tissues and gastric cell lines including GES-1, N87, SGC7901, BGC823 and PAMC82. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and Transwell assay were used to detect the proliferation and invasive ability of gastric cancer cells.RESULTSCompared to normal tissues, ANGPTL2 protein levels were significantly upregulated in gastric tissues, and this level was closely correlated with gastric tumor grade, clinical stage and lymph node metastasis. Compared to GES-1 cells, ANGPTL2 mRNA and protein levels were significantly increased in gastric cancer cells including N87, SGC7901, BGC823 and PAMC82. The expression of ANGPTL2 in highly malignant gastric cancer cell lines BGC823 and PAMC82 was significantly higher than in low malignancy gastric cancer cell lines N87 and SGC7901. MTT and Transwell experiments indicated that the proliferation rate and invasive ability of stable overexpressed gastric cancer cells was faster than in cells transfected with Lv-NC and blank control cells, and the invasive ability of stable overexpressed gastric cancer cells was higher than that of cells transfected with Lv-NC and blank control cells.CONCLUSIONANGPTL2 contributed to proliferation and invasion of gastric cancer cells. In clinical treatment, ANGPTL2 may become a new target for treatment of gastric cancer.

Gastric cancer is a major cause of cancer-associated mortality worldwide. The aberrant expression of microRNA (miRNA) is involved in tumorigenesis. Ras proteins transfer information from the extracellular environment to internal cellular compartments and are essential in numerous signal transduction pathways. To investigate the regulation, function and clinical significance of the miRNA377/Ras association domain family (RASSF) 8 signaling axis in gastric cancer, reverse transcription-quantitative polymerase chain reaction, immunohistochemistry, cell counting kit-8, western blotting, and Transwell assays were used. The results revealed that expression of RASSF8 was significantly upregulated in normal gastric tissues compared with gastric cancer, which was further confirmed by immunohistochemical analysis, and its expression level was increased in normal gastric cells compared with gastric cancer cell lines. However, the expression of miR-377 was significantly upregulated in gastric cancer compared with normal gastric tissues. In addition, RASSF8 overexpression in BGC-823 gastric cancer cells significantly inhibited the proliferation, apoptosis and invasive abilities of cells. Whereas miR-377 attenuated these effects due to downregulated RASSF8 expression by directly targeting its 3′-untranslated region. Furthermore, in the current study, miR-377 was not able to reverse the effects of RASSF8 overexpression on gastric cancer cells. Collectively, the RASSF8 gene may represent a novel molecular target involved in gastric cancer development and may be useful in targeted therapy of patients with gastric cancer.

Vaccination immunotherapy has revolutionized cancer treatment modalities. Although the immunomodulatory adjuvant generally employs for potentiating vaccine response, systemic administration may drive immune‐related side effects, even immune tolerance. Therefore, tunable immunoadjuvants are highly desirable to simultaneously stimulate the immune response and mitigate systemic toxicity. Self‐immolated nanoadjuvants are herein reported to potentiate vaccination immunotherapy of cancer. The nanoadjuvants are engineered by co‐assembling an intracellular acidity‐ionizable polymeric agonist of toll‐like receptor 7/8 resiquimod (R848) and polymeric photosensitizer pyropheophorbide a (PPa). The resultant nanoadjuvants specifically accumulated at the tumor site via passive targeting and are dissociated in the acidic endosome versicles to activate PPa via protonation of the polymer backbone. Upon 671 nm laser irradiation, PPa performed photodynamic therapy to induce immunogenic cell death of tumor cells and subsequently released R848 in a customized manner, which synergistically activated dendritic cells (DCs), promoted antigen cross‐presentation, and eventually recruited cytotoxic T lymphocytes for tumor regression. Furthermore, the synergistic in situ vaccination immunotherapy with immune checkpoint blockade induce sustained immunological memory to suppress tumor recurrence in the rechallenged colorectal tumor model.

Background: Circular RNA (circRNA) is a novel noncoding RNA (ncRNA) that assumes critical roles in tumor occurrence and progression. circRNA functions in many tumors as a kind of microRNA (mRNA) “sponge.” The present study sought to investigate the part played by circRNA in colorectal cancer (CRC) progression and to elucidate the relevant action mechanism(s). Methods: We detected lower hsa_circ_0077837 (circEPB41L2) expression in CRC by data analysis based on previous studies. We demonstrated the antitumor part of circEPB41L2 in CRC cells via a group of biological experiments. We subsequently took advantage of pull-down and dual-luciferase reporter assays to recognize circEPB41L2 downstream microRNA 21 (miR-21). Western blotting was conducted to confirm that the circEPB41L2–miR-21–phosphatase and tensin homolog (Pten)/AKT axis is responsible for CRC tumor growth suppression. The antitumor part of circEPB41L2 in vivo was eventually demonstrated by HCT116 xenograft model. Results: We found that circEPB41L2 overexpression inhibited the proliferation of CRC cells. Further, the miR-21 phenocopy suppressed circNRIP1 overexpression, while its overexpression also inhibited the cancer suppressive function of circEPB41L2. circEPB41L2 was confirmed to be able to inhibit tumor growth by enhancing Pten expression. Finally, the antitumor part of circEPB41L2 was confirmed. Conclusions: We demonstrated that circEPB41L2 sponges miR-21 to increase the Pten expression level and consequently serve as a cancer suppressor in CRC.